Dick Rutan, a swashbuckling legend in the aviation community, was sitting in his office at the Mojave airport in the Southern California desert when two engineers walked in with a big idea.  It was the spring of 2005, and Steven Weinzierl and Michael Fuchs had just developed a new piston engine that was both highly efficient and surprisingly quiet. While most small plane engines run on aviation gasoline — which is expensive and difficult to access — their innovative use of diesel mad